This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The specific aims are to: (1) evaluate drugs, pure compound(s) and natural product extracts using the egg-laying and the nicotine-motivated behavior assays in C. elegans, (2) isolate and characterize compounds of Vernonia cinerea using these assays in C. elegans, (3) perform mechanistic studies of isolated pure compounds using radioligand binding assays for nicotinic acetylcholine receptors (nAChRs), and (4) evaluate natural product extracts using assays in SA# 1 and #3.